Today, tens of thousands of runners from all over the world are hitting the streets, from Hopkinton to Boston, in the 2014 Boston Marathon. It’s always an inspiring scene to watch. But this year, in the aftermath of last year’s tragedy, the dedication and determination of each and every runner feels all the more profound. Putting one foot in front of the other for 26.2 miles is no easy feat, yet more people than ever are rising to the challenge.